Lead-acid storage batteries are typically formed of several cell elements which are encased in separate compartments of a container with sulfuric acid electrolyte. Each cell element typically includes at least one positive plate, at least one negative plate, and a separator positioned between each positive and negative plate. The positive and negative plates are generally a lead or lead alloy grid that supports an electrochemically active material, and in particular a lead based material (i.e., PbO, PbO2, Pb or PbSO4) pasted onto the grid. The grids provide an electrical contact between the positive and negative active materials which serves to conduct current.
It is known to provide sealed lead-acid batteries of one or more cells operating on the oxygen cycle with internal recombination of oxygen during charge and reasonable overcharge. These starved electrolyte batteries, or absorbed glass mat (AGM) batteries employ an absorptive separator mat preferably of micro-fine glass fibers having a large surface area per unit of volume and a large porosity, enabling retention of the bulk of the acid electrolyte (capacity determining) of the cell in the separator(s) while leaving a sufficiently thin layer of electrolyte on the active plate surface to sustain internal oxygen recombination within the cell at high efficiencies. Unfortunately, AGM batteries are more expensive than a typical flooded-cell type battery. In addition, such AGM batteries utilize expanded metal grids for the battery plates which are concast or book mold cast grids. Such grids, and the plates, cells and batteries made therewith are inefficient. In particular, the use of expanded metal grids results in low efficiency in the use of lead per performance output. Further, these expanded metal grids, when used in combination with stamped or alternative grids, require additional tooling and devices for manufacture, resulting in increased cost.